bff635be1d
We don't want such a mode to affect other uses of randomness, though. Thus use a separate random number generator object for these two functions, and use a fixed seed for it if the SC_RAND_REPEATABLE environment variable is set. As RAND() is implemented in sc, and RANDBETWEEN() is implemented in scaddins, it was a bit hard to figure out where to add the new functions needed, without having to over-engineer things with UNO. (This functionality is totally Calc-specific, but neither sc nor scaddins has any public (non-UNO) API.) Caolan suggested the formula module, which seems like a good enough place to me. Change-Id: I4b0cb327392e51a18bce28478af91b0174d6b726
57 lines
1.3 KiB
C++
57 lines
1.3 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#include <time.h>
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#include <random>
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#include <formula/random.hxx>
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#include <rtl/instance.hxx>
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namespace {
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struct CalcFormulaRandomGenerator
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{
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std::mt19937 aRng;
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CalcFormulaRandomGenerator()
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{
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// initialises the state of this RNG.
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// should only be called once.
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bool bRepeatable = (getenv("SC_RAND_REPEATABLE") != 0);
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aRng.seed(bRepeatable ? 42 : time(NULL));
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}
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};
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class theCalcFormulaRandomGenerator : public rtl::Static<CalcFormulaRandomGenerator, theCalcFormulaRandomGenerator> {};
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}
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namespace formula
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{
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namespace rng
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{
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double fRandom(double a, double b)
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{
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std::uniform_real_distribution<double> dist(a, b);
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return dist(theCalcFormulaRandomGenerator::get().aRng);
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}
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sal_Int32 nRandom(sal_Int32 a, sal_Int32 b)
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{
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std::uniform_int_distribution<sal_Int32> dist(a, b);
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return dist(theCalcFormulaRandomGenerator::get().aRng);
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}
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} // rng
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} // formula
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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